Transforming smelting-furnace.



H. HBLBERGBR.

TBANSFORMING SMELTING FURNACE.

APPLICATION FILED SEPT. 11,1908.

H. HELBERGER.

TRANSFORMING SMBLTING FURNACE.

APPLIUATION FILED szzr'r 11,1908

Patented Aug. 31, 1909.

3 BHEBTB-SHBBT 3.

HUGO HELBEBGEB, OF IURIGH, GEBIANY.

TRAHSFOBHNG SEEKING-FURNACE.

Epeoiflcaflon 0! Letters Patent.

Patented Aug. 31, 1909.

Application filed September 11, 1908. Serial No; 468,815.

To all whom it may Be it known'that I, Hnoo Hrusnnonn, a 5 subject of the Emperor of Germany,

mg at Munich, Germany, have invented certam new and usetul Improvements in Transforming Smel-ti by declare the fo lowing to be a full, clear, and exact description ot the same, reference had to the accompanying drawings, forming a part of this s ecification, and to the figures and letters 0 reference marked thereon.

This invention relates to appliances for melting, by means of electricity, metals,

lass, enamel and similar materials having a 'gh melting point, the objects of the invention being to provide a simple, thoroughly practical, compact and economical apparatus with which the materials operated on may be preserved without contamination or alteration other than such changes as are incidental to the heating of the same to the desincd degree.

The invention consists in certain novel details of construction and combinations and arran ments of parts, all as will be now descri ed and olnted out particularly in the a ended clziims.

In t e accompanying drawings: Figure 1 is a plective View of an apparatus embodymgt e present invention, certain arts, however, being omitted for the sake 0 per :picuity. Fig. 2 is a diagrammatic view of e apparatus. Figs. 3, 4, 5, 6 and 7 are views il-lnstrati receptacles for the material to be melt i "Similar letters of referenceindicate like parts in all the views.

It has been proposed heretofore to make use of melting vessels composed of gra bite and clog and the walls of which are highly heated the passage of an electric current, and whi e I do not claim the same broadly as my invention it is to be noted that there has been no commercial use of the idea, the apparatus heretofore proposed never having passed the experimental stage. i

,In the recent invention a practical and economics construction and arrangement of melting pot and appliances for heating the some is provided; thus as illustrated in Fi 2 there is provided a transformer T capab o of tzransformin an alternating or multiphase cumntofihi h potential and low can a into one. 0 low voltage and great cnsity or high amperage. The primary of resid- 1 the transformer is built up of coils in but each having one terminal tf leading to a switch or similar controller l. The high potential circuit from the coils includes a generator A and an ampere-meter B. -Furnaces; and I do here The transformer shown diagramnmtically in Fig. 2 is embodied in a structure forming part of the furnace, as shown in Fig. 1. The transformer is located within the fora-minous casin C held between thetop and bottom han s C and arms D projecting from the heads constitute the braces or sup.- ports for the terminal electrodes K, K, of the secondary whereby losses in the condoctors may be entirely avoided. The 11 per electrode K is movable whereby a me tin receptacle G may be clamped between it am. the lower electrode K. Conveniently the upper electrode is annular and controlled or advanced by a screw and hand wheel H.

Both electrodes are preferably water cooled for which purpose they form part of a water circulating system W W indleated in Fig. 2, but omitted from Fig. 1 toavoid obscurity. In this connection it may be mentioned that in order to avoid heat losses it is advantageous to place intermediate carbon contacts of high electrical conduotivity between the metal electrode and melting receptacle or crucible as indicated at k k l The melting rece tacle is the resistance element in the sec ary circuit and 1s preferabl made of graphite or a combination of ot er materials with graphite as will be presently explained, but it is here noted that m employing such vessels particular attention must be paid to regulation, since, as is well known, graphite has a negative temperature coeficient that is to say, the resist, anee decreases as. the temperature rises. The vol must therefore be reduced when the erucib .e becomes incandescent. For this reason especially, the graphite smelting vessel is placed in combination with the trans former since the latter is capable of regulation without loss. Operation by a direct current with resistance regulation is accomplished by such loss as to be commercially 1m racticable.

nasmueh as incandescence first appears in that mof the vesselhaving the greatest chemical resistance the form or construction oi'the vessel becomes of importance and if conductive material (metal) is to be mel ed it becomes of importance to confine the curesaeee rent to the walls of the vessel so as to iny from but engaging said-electrodes to clamp sure uniformity of 0 aeration and to prevent a crucible between them.

short circuiting.

hile ordinary crucibles f composed of a mixture of graphite and clay may be employed in the apparatus heretofore described, vessels constructed in accordance with the rinciples illustrated in Figs.

3 to 6 will be ound more advantageous.

with the walls intermediate the ends, of a reduceg cross section as at g, the points of reduce section being selected to accord with the points where the greatest concentration of heat is desired. 11 Figs. 5 and 6 the walls of the receptacles are composed of inients of varying pro ortions so as to increase the resistance at t e desired points, for instance, the ends of the receptacles. at 9' may be 6 parts cla while the portions 0 the wal 6 parts clay and 2 arts graphite and the mixtures may be 'duated heating from the maximum at nd 4 parts graphite 1 at 9' may be bended so as to secure;

the desired point of concentration to a mini- 1 mum at the points of contact with the electrodes.

When metal is to be melted it should be electrical] insulated from the wall ,of the vessel as y a non-conductive lining such, for instance, as fire brick but the desired result 'can best be accom lished by treating the vessel while white ot with an oxy en blast whereby the graphite on the sur ace is eliminated leaving a layer (9, Fig. 7) which is an insulator of electricity.

An air blast may be employed in lieu of the oxygen blast but requires a longer time to ive the desired result, so too other chemica treatment may be resorted to forremoving-the graphite from the inner surface of the receptacle, as, for example, treatment with fusible silicates also treatment with nitric-acid and potassium chlorate etc.

Vessels constructed as above described with a non-conductive inner surface may be used with equally good results for metals having a low me ng point (lead, tin, zinc etc.) or for metals having a high melti point (brass, copper, silver, gold, iron, stee etc.) and without such non-conductive inner surface the vessels may be advanta eously used. for melting or treating non-con uctive materials.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A transformer furnace embodying a transformer having terminal electrodes of its secondary windings located in proximity to and directly connected with the windings whereb current losses are reduced, said electroc es having oppositely disposed contact faces for clam mg a melting crucible between them and c amping means separate electror es having oppositely dispose In Figs. 3, fl and 7, the vessels are formed 7 the electrodes for supportin 3. A transformer furnace embodying a transformer having terminal electrodes of its secondary windings located in proximity to and directly connected with the windings whereby current losses are reduced, :1 frame in whic said transformer is mounted having arms projecting on the outer sides respectively of the terminal electrodes, and means carried by said arms and coiiperating with and moving the electrodes toward each at or to clamp a crucible between them. i

4. A transformer furnace embodying a transformer havin terminal electrodes of its secondary windings located in proximity to and directly connected with the windings whereby current losses are reduced, one of said electrodes being located above the other, a frame in which the transformer is mounted having top and bottom heads, rigid arms projectin from said heads above and beow the e ectrodes respectively, one of said arms forming a support against which one electrode rests and a clamping device on the other arm and coiiperating with the other electrode to clamp a crucible between the electrodes.

5. A transformer furnace embodying a transformer havin terminal electrodes of .its secondary win lugs oppositely disposed to clamp a crucible between them, both of said electrodes bein provided with internal ducts for the circu ation of a cooling medium.

6. A transformer furnace embodying an induction transformer, terminal electrodes for the secondary windin and a melting vessel held between said e ectrodes to form a part of the secondary circuit, said vessel havin integral walls of low conductivity with its interior face rendered electrically non-conductive by the elimination of the conductive material therefrom while the body and outer part remains conductive.

7. A transformer furnace embodying an inductive transformer, terminal electrodes for the secondary windin and a melting vessel heid between said e ectrodes to form a part '0 the secondary circuit, said vessel having integral walls with graphite embodied therein to form a conductive element and having its inner face rendered electrically non-conductive by the elimination of the graphite while its body and outer part remains conductive. V

8. A transformer furnace embodying an inductive trans'former,. terminal electrodes for the secondary windin i and a melting vessel held between said e ectrodes to form a part of the secondary circuit, said vessel hgvi integral walls withgraphite embodi therein to form a conductive element and having the inner face rendered electrically non-conductive by blowing oxygen into 15 the vessel when heated by the passage of current therethrough.

HUGO HELBERGER.

Witnesses:

LOUIS MUELLER, MATHILDE K. HELD. 

